TRENTON, N.J. -- The New Jersey Department of Health says a woman who arrived at Newark Liberty International Airport from West Africa and was the first traveler to be quarantined under new Ebola protocols has developed a fever.

The woman, a health care worker who had been treating Ebola patients in Sierra Leone, is in isolation and being evaluated at University Hospital in Newark, according to CBS New York.

The Department of Health could not say what flight the woman was on or whether other passengers were involved.

Dr. Howard Zucker, acting New York state health commissioner, said any medical personnel who have treated Ebola patients in Sierra Leone, Guinea and Liberia will be automatically isolated for 21 days, the maximum incubation period for the virus, either at their homes or a medical facility.

The order came one day after Dr. Craig Spencer was diagnosed with Ebola, the first case in New York. The 33-year-old emergency room doctor returned to the U.S. on Oct. 17 after treating Ebola patients in Guinea with Doctors Without Borders.

Spencer sought treatment Thursday after suffering diarrhea and a 100.3-degree fever. He was listed in stable condition at a special isolation unit at Bellevue Hospital Center, and a decontamination company was sent to his Harlem home. His fiancee, who was not showing symptoms, was being watched in a quarantine ward at Bellevue.

Dr. Irwin Redlener, an advisor to New York Mayor Bill de Blasio, said Friday afternoon that Spencer is in "relatively stable" condition, adding that the patient was not "out of the woods" yet, but the chances of his condition dramatically worsening were "very, very limited."

Travelers at Newark Airport Friday night told CBS New York the new, stricter measures are necessary.

"I think it's a sensible thing to do," said passenger Dave Fairfax. "I mean, it's a big problem in Africa right now, and you know, we've seen already that it can spread to the U.S. We've had cases here. So I'm in favor of it personally."

"I think it's important to take it seriously," added traveler Kate O'Connor. "I don't know about mandatory stuff, that's kind of scary. But it s serious. I work in health care so I'm concerned."

Officials said they would track flight connections and screen passengers upon disembarking. However, they offered few details on how the quarantine would be enforced and what the consequences would be for people who violated the restrictions by going out in public.

A spokesman for New York City Mayor Bill de Blasio said the city's Department of Health was not consulted before the quarantine order came down, but said de Blasio and Cuomo have since spoken.

The de Blasio administration expressed some concern with the policy change, the first crack in what had been a calibrated show of cohesion across levels of government.

"The mayor wants to work closely with our state partners, but he wants to make sure that there will not be any sort of chilling effect on medical workers who might want to go over to help," said spokesman Phil Walzak.

The White House did not have an immediate reaction to Cuomo and Christie's directives. Officials said Friday the administration was regularly reviewing its policies but indicated they were satisfied with the measures it has put in place, including steps that call on recent arrivals from West Africa to monitor their health and notify state and local authorities of their presence in their communities.

The Obama administration has said states are entitled to impose additional requirements beyond those set by the CDC. The CDC said it sets baseline recommended standards, "but state and local officials have the prerogative to tighten the regimen as they see fit."

The agency also said, "When it comes to the federal standards set by the CDC, we will consider any measures that we believe have the potential to make the American people safer."

Spencer's illness led lawmakers on Capitol Hill, scientists and ordinary New Yorkers to wonder why he was out on the town after his return -- and why stronger steps weren't being taken to quarantine medical workers.

Health officials said he followed U.S. and international guidelines in checking his temperature every day and watching for symptoms, and that he put no one at risk. But others said he should have been quarantined, either voluntarily or by the government, during the incubation period.

An automatic three-week quarantine makes sense for anyone "with a clear exposure" to Ebola, said Dr. Richard Wenzel, a Virginia Commonwealth University scientist who formerly led the International Society for Infectious Diseases.

Aid organizations such as Doctors Without Borders, the group Spencer was working for, have argued that mandatory quarantines are unnecessary because people with Ebola aren't contagious until symptoms begin, and even then it requires close contact with body fluids.

Also, aid groups have warned that many health care volunteers wouldn't go to Ebola hot zones if they knew they would be confined to their homes for three weeks after they got back.

"A three-week complete quarantine would eliminate two-thirds to three-quarters of the volunteers from the U.S." going to West Africa, said Dr. Rick Sacra, a Massachusetts physician who was recently infected in Liberia but recovered. "They wouldn't be able to spare the time."

On the streets of New York, Michael Anderson was critical of the U.S. government and Spencer.

"He's stupid, a complete idiot" for moving about in public, the longtime Manhattan resident said at Grand Central Station. "It's his responsibility when you come back from Africa" not to put people at risk, he said.